A number of cutting apparatuses designed to shear or trim roofing shingles have been constructed and marketed, but most roofers continue to rely upon utility knives and straight-edges for cutting shingles because of the ease the knives' portability and simplicity of use, as well as the ease and low cost of replacing dulled blades as compared to existing cutting apparatuses. Most existing apparatuses are cumbersome to move and provide inferior cutting results when contrasted with the utility knife. Therefore, there exists a need in the art for a portable shingle cutting apparatus which provides ease of portability and use, as well as shearing performance equivalent to or better than the cutting quality provided by utility knives.